ISSN:0193-7197    

DOI:10.1002/vnl.730160202

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

ISSN:0193-7197    

DOI:10.1002/vnl.730160203

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper presents the basic principles of SPC charts and how to employ SPC techniques in performing simple measurement accuracy and precision studies. Information on the concepts of variation, basic statistics, the normal distribution, and the central limit theorem are presented to set the foundation for SPC. With these concepts in place, it is possible to introduce the two SPC charts on which accuracy and precision studies can be based—individuals charts and X‐bar charts. Many other types of control charts exist that are not described in this paper, specifically, control charts for attributes data. These are generally not applicable to measurement accuracy and precision studies, and numerous texts are available that sufficiently detail control charts for attributes d

ISSN:0193-7197    

DOI:10.1002/vnl.730160204

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractExperiments generate data. Data generate results. Results lead to decisions. Decisions solve problems. Right??? Well, not always. Things can go wrong….At the root of the above sequence is data. If the data are not good, the problem is unlikely to get solved. If the data are good, but not properly interpreted, the problem may persist.One cause of poor data is a poor experimental design. Once run, the results cannot be improved by the best data analysis techniques. Given good data, interpretation can change the conclusions. Data analysis techniques are available that enable the experimenter toCorrect for process drift during a series of experiments.Study data for outliers, which can falsely influence results.Determine distribution of data within and between data sets.Do regression analysis to establish mathematical relationships.These techniques lead to statistically correct identification of cause and effect relationships, or show that none are present in the data. Rigorous data analysis produces fewer disappointments and more problem solution

ISSN:0193-7197    

DOI:10.1002/vnl.730160205

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractIn this work we present the optimization of the processing conditions for PVC plastisol rotational molding. The effects of oven temperature, processing time, rotational, speed and amount of plastisol over the degree of curing, physical appearance, and mechanical properties of the molded articles were studied. Also, using a simple mathematical model to simulate the temperature profiles of the plastisol inside of the spherical mold as a function of time, the viscosity change of the plastisol with time is reported. A rotational molding machine laboratory size was used for the experiments. The oven (at different points) as well as the mold (at the inside and outside of the cavity) temperatures were measured as a function of time in order to get a better understanding of the curing process. Such data in conjunction with the model gives the support for process optimization and control.

ISSN:0193-7197    

DOI:10.1002/vnl.730160206

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractThe use of multiphase polymers is of growing importance given their inherent economical and technological benefits. Unplasticized PVC is brittle and heat sensitive. Improved impact resistance is often attained by using rubber additives. However, the rubber contributes to increasing viscosity, and, consequently, limited processability. Research efforts are concentrated on the development of a PVC matrix blend that has good heat stability and processability. While traditional PVC modification has concentrated on using plasticizers to aid processing, in this project, the use of three styrenic copolymers has been investigated. Miscibility of the systems has been established using the Rheometrics Mechanical Spectrometer by determining the number of transitions in the resultant blends. Long range time‐temperature effects have been established via generation of master curves for the two component systems. The shift factor data has been analyzed to determine the corresponding activation energies associated with different transitions. These indicate a methodology to design optimum blend system

ISSN:0193-7197    

DOI:10.1002/vnl.730160207

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractPoly(vinyl chloride) compounds offer a wide range of properties from elastomeric to rigid. For this reason they are well suited for many extrusion applications. However, many processors shy away from PVC because of its challenging process‐ability: PVC is shear sensitive, susceptible to thermal degradation, and highly elastoviscous. This study, although limited, attempts to remove some of the complexity behind PVC extrusion. A semirigid PVC compound was processed on a small laboratory extruder. A factorial experiment was followed to determine the effects of barrel temperature and screw speed on melt temperature, residence time, output, and head pressure. Understanding these fundamental relationships is intrinsic to successful PVC extrusio

ISSN:0193-7197    

DOI:10.1002/vnl.730160208

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractThe use of a newly developed ABS impact modifier in coextruded vinyl siding and window profile substrate is discussed. Considerations of toughness at room and low temperature, output, reduced lubricant levels, and weatherability of the finished siding are reviewed. Actual outdoor weathering results are presented, along with long‐term heat aging tests, showing the modifier to have good property retention characteristic

ISSN:0193-7197    

DOI:10.1002/vnl.730160209

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractLubricants are used in extrusion processing of rigid polyvinyl chloride (PVC) compounds to control fusion and reduce shear heating. Without lubricants, conversion to the melt state results in excessive shear heating and degradation of the compound. The present work compares new lubricant systems containing complex esters with conventional systems based on ethylene bisstearamide (EBS) and paraffin. These new systems provide improved compound stability, weatherability, and physical properties. In addition, use of these systems results in lower compound viscosity compared with the conventional lubricant packages. The effects of other characteristics of these systems, such as the degree of esterification on compound properties, are also discussed.

ISSN:0193-7197    

DOI:10.1002/vnl.730160210

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractPerhaps as much as 75% of the material placed on exposure in outdoor test fields or in laboratory accelerated testing devices is on test because of a specification requirement that is a part of the condition of sale. Government standards, automotive manufacturers' specifications, and many architectural guidelines are filled with directives instructing prospective suppliers to expose the candidate material to specific weather durability criteria before they submit their product for consideration or acceptance. Approximately another 15% of the materials on exposure is for product warranty. Results from exposures performed in harsh climatic environments to a known industry standard are used to back up claims of product or material durability. Finally, there is a 10% group using exposure sites and laboratory weathering machines for research and development. An ever‐increasing demand for new and more durable products has made the seemingly simple task of weathering a key part of product development, quality assurance, and warranty. Even with the rapid technological improvements in field exposures, laboratory machines, test methods, and evaluation techniques there is mystery, mistrust, and misunderstanding of the weathering process. This paper discusses the reasons for and choices to be made when considering a program for assessing the ability of materials to resist degradation due to weatherin

ISSN:0193-7197    

DOI:10.1002/vnl.730160211

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY